Subject: Re: [Geopriv] [geopriv] #4: Uncertainty semantic for resolution fields

From: "geopriv issue tracker" <[email-masked]>
Date: Thu, 10 Sep 2009 06:18:32 -0000

#4: Uncertainty semantic for resolution fields
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 Reporter:  [email-masked]  |        Owner:  [email-masked]          
     Type:  defect           |       Status:  new                       
 Priority:  major            |    Milestone:  draft-ietf-geopriv-3825bis
Component:  rfc3825bis       |      Version:                            
 Severity:  -                |   Resolution:                            
 Keywords:                   |  
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Comment(by [email-masked]):

 I have made a start at attempting to resolve this comment, based on
 inclusion of a Section 1.2 Resolution and Uncertainty, and incorporation
 of Section 2 from draft-thomson:
 http://www.drizzle.com/~aboba/GEOPRIV/draft-ietf-geopriv-rfc3825bis-02.txt

 There is still some work to do to fill in the missing pieces as indicated
 by Martin.

-- 
Ticket URL: <https://trac.tools.ietf.org/wg/geopriv/trac/ticket/4#comment:5>
geopriv <http://tools.ietf.org/geopriv/>

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From: "geopriv issue tracker" <[email-masked]>
Date: Fri, 11 Sep 2009 18:36:11 -0000

Here is what Section 1.2 currently looks like:

 1.2.  Resolution and Uncertainty

    The DHCPv4 option format defined in this document utilizes both
    resolution and uncertainty parameters.  The DHCPv6 option format only
    utilizes an uncertainty parameter.

    Version 0 of the DHCPv4 option format defined in this document
    includes a resolution parameter for each of the dimensions of
    location.  Since this resolution parameter need not apply to all
    dimensions equally, a resolution value is included for each of the 3
    location elements.  Resolution does not define Geographic Privacy
    policy.

    Appendix A of this document provides some arithmetic examples of the
    implication of different resolution values on the La/Lo/Alt.

    The DHCPv6 option format as well as version 1 of the DHCPv4 option
    format utilizes an uncertainty parameter.  In the context of location
    technology, uncertainty is a quantification of errors.  Any method
    for determining location is subject to some sources of error;
    uncertainty describes the amount of error that is present.
    Uncertainty might be the coverage area of a wireless transmitter, the
    extent of a building or a single room.

    Uncertainty is usually represented as an area within which the target
    is located.  In this document, each of the three axes can be assigned
    an uncertainty value.  In effect, this describes a rectangular prism.

    When representing locations from sources that can quantify
    uncertainty, the goal is to find the smallest possible rectangular
    prism that this format can describe.  This is achieved by taking the
    minimum and maximum values on each axis and ensuring that the final
    encoding covers these points.  This increases the region of
    uncertainty, but ensures that the region that is described
    encompasses the target location.

 Comments?

-- 
Ticket URL: <http://trac.tools.ietf.org/wg/geopriv/trac/ticket/4#comment:6>
geopriv <http://tools.ietf.org/geopriv/>